Locking device for duplicating and printing machines



M. JAUCH July 13, 1954 '3 Sheets-Sheet l INVENTOR Martin Jouch BY 4* 5 I A ORNEYS LOCKING DEVICE FOR DUPLICATING AND PRINTING MACHINES M. JAUCH July 13, 1954 LOCKING DEVICE FOR DUPLICATING AND PRINTING MACHINES Filed Dec. 22, 1950 3 Sheets-Sheet 2 Martin Jauch ATTORNEYS L M. JAUCH July 13, 1954 LOCKING DEVICE FOR DUPLICATING AND PRINTING MACHINES Filed Dec. 22, 1950 3 Sheets-Sheet 3 'Hll INVENTOR Martin Jouch A ORNEYS Patented July 13, 1954 LOCKING DEVICE FOR DUPLICATING AND PRINTING MACHINES Martin Jauch, Konigslutter, Germany Application December 22, 1950, Serial No. 202,213

1 Claim. 1 This invention relates to duplicating and printing machines, and refers more particularly to a device constituting a part of a duplicating machine using a spirit liquid for moistening the paper, said device preventing rotation of the counter-pressure roller on the printing cylinder,

when a sheet of paper has not been fed thereto.

Roller-locking means of the ordinary manifolding machines, such as stencil duplicating machines, cannot be used in offset printing and similar reverse printing machines because the counter roller is pressed with a heavy pressure against the printing cylinder. The power necessary for counteracting this heavy pressure is not available in small machines such as are used in ofiices and for duplicating purposes. The operator of a hand operated machine cannot be expected to have the strength necessary to move the counter-pressure roller away from the printing cylinder. In the case of motor-driven machines, the power of the driving motor must be greatly increased if the pressure by which the counterroller is pressed against the printing cylinder is to be overcome, which involves a considerable waste of power.

An object of the present invention is to eliminate these drawbacks and to provide simple and efiectively operating means for preventing rotation of the pressure roller when there is no supply of paper.

Other objects of the present invention will become apparent in the course of the following specification.

The present invention is based essentially on the realization that the locking problem, when a sheet of paper has not been fed to the machine, can be solved in a simple manner, if the printing cylinder and not the counter-pressure roller is locked and prevented from further rotation. The locking element need not directly engage the printing cylinder but it may equally well engage a hand lever or crank or a Wheel of the transmission between the hand lever and the cylinder. It is also possible to fit on a driving shaft a separate disc which carries the looking members.

Arrangements pertaining to hand-operated machines also hold good for electrically driven machines in which case the driving wheel or pulley takes the place of the hand lever. One of the important features is that the printing cylinder is locked, the member which effects the locking being arranged to act on any rotating wheel or the like interposed between the driving means and the printing cylinder.

The arrangement can be carried out, for example, in such a manner that a feeler, which contacts the sheets of paper fed to the machine, retains in locking position a locking device which prevents movement of the printing cylinder when a sheet of paper is lacking until a freshly supplied sheet of paper moves the feeler fromthe looking device and releases it.

It is important that the feeler should be as near as possible to the line of contact of the two cylinders. The nearer the feeler spring is brought to the line of contact of the two cylinders the less is the danger that the device may not satisfactorily fulfill its purpose. Between the end of the feeler spring and the said line of contact the device is ineffective. This zone must be kept as small as possible. The smaller the two cylinders are the easier does this become. The feeler spring is, therefore, preferably arranged not between the printing cylinder and the counter-pressure roller but between two of the conveyor rollers which are usually present.

The invention will appearmore clearly from the following detailed description when taken in connection with the accompanying drawings showing, by Way of example, a preferred embodiment of the inventive idea.

In the drawings:

Figure 1 is a side view of the apparatus constructed in accordance with the present invention during the passage of a sheet of paper;

Figure 2 is an end view of the apparatus of Figure 1;

Figure 3 is a top View thereof;

Figure 4.- is a view similar to Figure 1 after a sheet of paper has passed through the apparatus;

Figure 5 is an end view of the apparatus of Figure 3;

Figure 6 is a top view thereof;

Figure 7 is a view similar to Figures 1 and 3 showing the position of the parts when a sheet of paper has not been fed to the apparatus; and

Figure 8 is an end elevation of the apparatus of Figure 5;

Figure 9 is a top view thereof.

Referring to the drawings, the locking device of the present invention is adapted for use in a so-called spirit duplicator, namely, a duplicating machine which uses a spirit liquid for moistening the paper. This machine includes a printing cylinder H] which cooperates with a counterpressure roller H. A moistening roller l2 cooperates with a feed roller l3. The sheet of paper [4 slides over a table I5. Other parts of the machine have not been illustrated since they are not necessary to the understanding of the present invention.

The locking device of the present invention includes a two-armed lever iii of which the arm I? carries a lug l8 and a guide roller 19. The second arm 20 of the lever i6 is provided with a guide pin 2i and is drawn by a tension spring 22 towards a stop 23. One end of the spring 22 is attached to the arm ll of the lever it, while the other end of the spring 22 is connected to a pin 24 mounted on the casing wall 25. The stop 23 is also supported by the casing.

On the front face of the printing cylinder 19' there is provided a cam 26 which coacts with the guide roller i9, and a stop 27 which coacts with the lug I8.

The locking device is operated by one or more feeler springs 28 which form one arm of a twoarmed lever 29 which can turn about a pivot 39 fixed in the casing wall 25. It will be noted that the feeler 28 is located so. close to the line of contact of the paper M and the feed rollers 13 that there is practically no ineffective zone. The second arm 31 of the lever 29 cooperates with the pin 2| of the locking device and is acted upon by a spring 32 which presses the feeler 23 against the sheet of paper H; which is fed tothe apparatus.

The sheet of paper [4 slides over the table it in which, at the place where the feeler 28 would lie when no sheet of paper is fed to the table, is an opening 33 into which the feeler 28 can enter.

In the example illustrated,.the locking device is pivoted on the axis of the moistening roller 32 n which cooperates with the feed roller 53.

Obviously, however, the locking device can also be arranged directly in front of the printing cylinder I6 which cooperates with the counterpressure roller l I but the feeler spring 28 cannot then be brought so close to the line of contact of the cylinder it and roller i I because the diameter of the cylinder iiiis too great.

For hand operation a lever 3 which is illustrated diagrammatically is provided.

The method of operation of the device is as follows:

At each revolution of the printing cylinder ID the cam 25 bears against the guide roller 19 and presses it aside, whereby the lug I8 ismoved intothe path of the stop 2?. At the same time the pin 2| on the arm 23 slides along the lever 31 and the feeler 28. As long as a sheet of paper 54 is on the table i the lever arm 29 is not influenced by the arm 3i so that the guide roller l9 and the arm H can again spring inwardly as soon as the roller it has passed over the cam 26. If, on the other hand, there is no sheet of paper [4 on the table it, then under the action of a spring 32 the end of the feeler tends to enter into the opening 33 of the table 55. This tendency becomes greater the further the pin 2! on the arm 26 slides downwardly along the arm 3!. When the arm as has arrived at its lowest position and the lug i8 is in the path of the stop 21, the pin 2i snaps into a recess 35 provided for it in the arm 3| and is held fast in this position, because the spring 32 presses the arm 31 against the pin 2i in the recess 35. Then the entire locking device is blocked, as shown in Figures '7 and 8, and cannot again return to its normal position shown in Figure 5 when the roller I9 leaves the cam 26.

The release of the locking device is effected by inserting a sheet of paper below the feeler 28 or by operating the hand lever 34, whereby the feeler is again pushed out of the openings whereby the pin 2! and the arm 28 are freed and the arm returns to its normal position under the action of the spring 22. The lug I8 is at the same time Withdrawn from the stop 2'! so that the printing roller can again rotate freely.

It is apparent that the examp e shown above has been given solely by way of illustration and not by way of limitation.

What is claimed is:

In a duplicating and printing machine having a rotary printing cylinder, a counter-pressure roller cooperating with said printing cylinder, and a table supplying sheets to be printed to said printing cylinder, a device locking said printing cylinder when a sheet of paper has not been fed thereto to prevent rotation of the counter-pressure cylinder on the printing cylinder, said device comprising two two-armed levers, means swingably supporting said two-armed levers, a guide pin carried by an arm of one of said twoarmed levers and adapted. to engage an arm of the other one of said two-armed levers, the second arm of said other two-armed lever being adapted to engage a sheet of paper upon said table, whereby said sheet maintains said other two-armed lever in an inoperative position, a guide roller carried by the other arm of said one two-armed lever, a cam carried by said printing cylinder and adapted to engage said guide roller, whereby said one two-armed lever is swung by the sliding engagement of said cam with said guide roller in the course of rotation of said printing cylinder, said guide pin sliding upon the one arm of said other two-armed lever during the swinging of the one two-armed lever and while the other two-armed lever is maintained in an inoperative position, means moving said other two-armed lever into an operative locking position when there is no sheet of paper upon said table, said one arm of said other two-armed lever having a recess formed therein and adapted to receive said guide pin when said other two-armed lever is in said locking position, a lug carried by the other arm of said one two-armed lever, and a stop carried by said cylinder and adapted to engage said lug when said guide pin is in said recess, whereby the engagement of said stop with said lug locks said printing cylinder.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,358,401 Knauer Sept. 19, 1944 2,553,911 Gerlach May 22, 1951 2,567,493 Oden Sept. 11, 1951 FOREIGN PATENTS Number Country Date 595,207 France Sept. 29, 1925 

